Properties of sol-gel SnO{sub}2/TiO{sub}2 electrodes and their photoelectrocatalytic activities under UV and visible light illumination

摘要

A visible light active binary SnO{sub}2-TiO{sub}2 composite was successfully prepared by a sol-gel method and deposited on Ti sheet as a photoanode to degrade orange II dye. Titanium and SnO{sub}2 can promote the development of rutile phase of TiO{sub}2 and inhibit the formation of anatase phase of TiO{sub}2. Formation of SnO{sub}2 crystalline is insignificant even when the calcination temperature increases to 700℃. Heterogenized interface between SnO{sub}2 and TiO{sub}2 inhibits growth of TiO{sub}2 linkage and leads to the particle-filled surface morphology of SnO{sub}2-containing films. The carbonaceous, Ti-O-C bonds and Ti{sup}(3+) species are likely to account for the photoabsorption and photoelectrocatalytic (PEC) activity under visible light illumination. The electrode with 30% SnO{sub}2 exhibits higher photocurrent when compared with those in the region of 0-50%. The 600℃-calcined SnO{sub}2-TiO{sub}2 electrode indicates higher activity when compared with those at 400, 500, 700 and 800℃. PEC degradation of orange II follows the Langmuir-Hinshelwood model and takes place much effectively in a solution of pH 3.0 than those in pH 7.0 and pH 11.0.